Air: Study Notes for Class 6 Science

Introduction to Air
Air is the invisible mixture of gases that surrounds the Earth. It is a fundamental part of our environment and essential for the survival of all living organisms. Air is composed of several gases, including nitrogen, oxygen, carbon dioxide, and traces of other gases.

Composition of Air
- Nitrogen: Nitrogen is the most abundant gas in the air, making up about 78% of its composition.
- Oxygen: Oxygen is the second most abundant gas in the air, constituting approximately 21%.
- Carbon Dioxide: Carbon dioxide is present in trace amounts, about 0.04%.
- Other Gases: The remaining portion of air contains small amounts of argon, neon, helium, and other gases.

Importance of Air
- Breathing: Air is vital for the process of respiration in living organisms, including humans. It provides oxygen needed for the production of energy in cells.
- Combustion: Air is necessary for the burning of fuels, such as wood, coal, and gas. It provides oxygen for the combustion process.
- Weather and Climate: Air plays a significant role in the formation of weather and climate patterns. Wind, storms, and rain are all influenced by air movements.
- Protection: The layer of air around the Earth, known as the atmosphere, acts as a protective shield against harmful solar radiation and meteorites.

Physical Properties of Air
- Air has mass and occupies space.
- It is compressible, meaning its volume can be changed by applying pressure.
- Air exerts pressure on all objects in its surroundings.
- It can be expanded by heating and contracted by cooling.

Air Pollution
Air pollution occurs when harmful substances, such as smoke, gases, and particulate matter, are released into the air, leading to a decrease in air quality. It can have detrimental effects on human health, ecosystems, and the overall environment. The major sources of air pollution include industrial emissions, vehicle exhaust, and burning of fossil fuels.

Conclusion
Understanding the composition and properties of air is crucial for comprehending various scientific concepts and phenomena. It is essential to promote clean air practices and reduce air pollution to ensure a healthy environment for all living beings.

Air is mixture of gases....